Abstract
Inorganic sulfide solid-state electrolytes, especially Li(6)PS(5)X (X = Cl, Br, I), are considered viable materials for developing all-solid-state batteries because of their high ionic conductivity and low cost. However, this class of solid-state electrolytes suffers from structural and chemical instability in humid air environments and a lack of compatibility with layered oxide positive electrode active materials. To circumvent these issues, here, we propose Li(6+x)M(x)As(1-x)S(5)I (M=Si, Sn) as sulfide solid electrolytes. When the Li(6+x)Si(x)As(1-x)S(5)I (x = 0.8) is tested in combination with a Li-In negative electrode and Ti(2)S-based positive electrode at 30 °C and 30 MPa, the Li-ion lab-scale Swagelok cells demonstrate long cycle life of almost 62500 cycles at 2.44 mA cm(-2), decent power performance (up to 24.45 mA cm(-2)) and areal capacity of 9.26 mAh cm(-2) at 0.53 mA cm(-2).